Combination CPAP and resuscitation systems and methods

ABSTRACT

A combination positive airway pressure (PAP) or continuous positive airway pressure (CPAP) and resuscitation system and related methods. The systems can be well-suited for use in providing CPAP therapy for a neonate or infant patient, with the ability to also provide resuscitation therapy at a peak inspiratory pressure (PIP) as needed or desired without switching to another system or switching the patient interface. The system can include an expiratory pressure device capable of regulating a positive end expiration pressure (PEEP) of the system, which preferably can also induce pressure oscillations relative to a mean PEEP.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference in their entireties andmade a part of the present disclosure.

BACKGROUND Field of the Invention

The present invention relates to breathing assistance systems andmethods. In particular, the present invention relates to systems andmethods for providing positive airway pressure therapy or resuscitationtherapy to an infant.

Description of the Related Art

Under certain circumstances it is necessary or desirable to providebreathing assistance to a patient under respiratory distress. Forexample, breathing assistance is often a necessary therapy to treatrespiratory distress syndrome (RDS) in infants, which can also bereferred to as neonatal respiratory distress syndrome or respiratorydistress syndrome of newborn. The breathing assistance provided is oftenin the form of providing breathing gases at a positive pressure, or apressure somewhat greater than atmospheric pressure. Such treatments maybe referred to in general as positive airway pressure (PAP) therapy.Often, the positive pressure is provided by a continuous flow ofbreathing gases, which is referred to as continuous positive airwaypressure (CPAP) therapy. Infants on CPAP therapy to treat respiratorydistress syndrome may also be likely to stop breathing and requireresuscitation therapy.

SUMMARY

A preferred embodiment is a combination positive airway pressure andresuscitation system and, preferably, a continuous positive airwaypressure and resuscitation system, as well as methods relating to theset-up and use of such a system. Conventionally, in response to RDS, aninfant is treated with a PAP system for an extended period of time. Ifnecessary, a separate resuscitation system is utilized to provideresuscitation. Subsequently, the use of the PAP system is resumed. Thismethod results in inefficiencies caused by the switchover from onesystem to the other. In particular, the patient interface is usuallyswitched when going from one system to the other, which can be timeconsuming and disruptive to the infant. The preferred systems andmethods allow PAP or CPAP therapy for extended periods, along withintermittent resuscitation, in a quick and efficient manner and withoutrequiring the patient interface to be changed.

A preferred embodiment involves a combination infant positive airwaypressure and resuscitation system, including an integrated inspiratorypressure device comprising a resuscitator and a humidifier. Theresuscitator is capable of regulating a flow of breathing gas to adesired peak inspiration pressure. The humidifier humidifies the flow ofbreathing gas. An expiratory pressure device is configured to receiveexpiratory gases from an expiratory circuit and regulate the expiratorygases to a positive end expiration pressure. An occlusion device iswithin the expiratory circuit upstream from the expiratory pressuredevice and is configured to permit occlusion of the expiratory circuitat desired times such that the pressure within the inspiratory circuitrises to the peak inspiration pressure of the resuscitator.

In some embodiments of the above-described system, the resuscitator isseparable from the humidifier. The resuscitator can be integrated with afirst housing and the humidifier can be integrated with a secondhousing. Some of the above-described system can include a flow generatorthat generates the flow of breathing gas. The flow generator can beintegrated with the second housing.

A preferred embodiment involves a combination infant positive airwaypressure and resuscitation system. The system includes an inspiratorypressure device that outputs a flow of breathing gas at a desired peakinspiration pressure to an inspiratory circuit. A patient interfacereceives the flow of breathing gas from the inspiratory circuit, whereinthe patient interface is configured to deliver the flow of breathing gasto an infant patient and receive expiratory gases from the patient. Anexpiratory circuit receives the expiratory gases from the patientinterface. An expiratory pressure device receives expiratory gases fromthe expiratory circuit and regulates the expiratory gases to a positiveend expiration pressure. An occlusion device is positioned within theexpiratory circuit upstream from the expiratory pressure device. Theocclusion device is configured to permit occlusion of the expiratorycircuit at desired times such that the pressure within the inspiratorycircuit rises to the peak inspiration pressure.

Another preferred embodiment involves a combination infant positiveairway pressure and resuscitation system. The system includes a supplyof breathing gas and an inspiratory pressure device that receives a flowof breathing gas from the supply of breathing gas. The inspiratorypressure device is capable of outputting the flow of breathing gas at adesired peak inspiration pressure to an inspiratory circuit. A patientinterface receives the flow of breathing gas from the inspiratorycircuit, wherein the patient interface is configured to deliver the flowof breathing gas to an infant patient and receive expiratory gases fromthe patient. An expiratory circuit receives the expiratory gases fromthe patient interface. An oscillatory expiratory pressure devicereceives expiratory gases from the expiratory circuit and regulates theexpiratory gases to a mean positive end expiration pressure withpressure oscillations relative to the mean pressure. An occlusion deviceis positioned within the expiratory circuit and is configured to permitocclusion of the expiratory circuit at desired times such that thepressure within the inspiratory circuit rises to the peak inspirationpressure.

In some arrangements of the above-described systems, the expiratorypressure device is or includes a water resistance valve, which can beadjustable to permit adjustment of the positive end expiration pressure.The occlusion device can be a manual push button valve or a clamp valve,among other possible valve types. In some arrangements, the system caninclude a humidifier positioned within the inspiratory circuit betweenthe inspiratory pressure device and the patient interface. Preferably,the occlusion device is located less than 500 millimeters from thepatient end of the expiratory circuit. In some arrangements, theexpiratory circuit can include an expiratory hose coupled to the patientinterface and the occlusion device can be located within the expiratoryhose.

In some arrangements, a source of breathing gas is provided separatelyfrom the inspiratory pressure device, such as via a bottle or wallsource. In other arrangements, the source of breathing gas is ambientair and a flow of air is generated by a flow generator or blower. Theblower can be provided in an integrated unit with the inspiratorypressure device (e.g., resuscitator) and the humidifier. In somearrangements, the blower and humidifier are contained or associated witha first housing and the inspiratory pressure device (e.g., resuscitator)can be integrated with a second housing, which can be removed from thefirst housing. In some arrangements, the humidifier is contained orassociated with a first housing and the inspiratory pressure device(e.g., resuscitator) can be integrated with a second housing, which canbe removed from the first housing. In some arrangements, the blower canbe integrated with the humidifier and the inspiratory pressure device(e.g., resuscitator) can be a separate component.

Another preferred embodiment involves a combination infant positiveairway pressure and resuscitation system. The system includes a patientinterface that receives expiratory gases from the patient and anexpiratory circuit that receives the expiratory gases from the patientinterface. An expiratory pressure device receives expiratory gases fromthe expiratory circuit and regulates the expiratory gases to a positiveend expiration pressure. An occlusion device is positioned within theexpiratory circuit upstream from the expiratory pressure device and isconfigured to permit occlusion of the expiratory circuit at desiredtimes such that the pressure within the system rises above the positiveend expiration pressure.

A preferred embodiment involves a breathing circuit for a combinationinfant positive airway pressure and resuscitation system. The circuitincludes an expiratory circuit that is configured for connection to apatient interface to receive expiratory gases from the patient interfaceand an inspiratory circuit that is configured for connection to thepatient interface to deliver a flow of breathing gas to the patientinterface. An occlusion device is configured to permit occlusion of theexpiratory circuit at desired times such that the pressure within thesystem rises above the positive end expiration pressure.

In some arrangements of the above-described circuits, the expiratorycircuit is further configured for connection to an expiratory pressuredevice that receives expiratory gases from the expiratory circuit andregulates the expiratory gases to a positive end expiration pressure.The occlusion device can comprise a manual push button valve. Theocclusion device can comprise a clamp. The occlusion device can belocated less than 500 millimeters from the patient interface along theexpiratory circuit. The occlusion device can be located in theexpiratory circuit. In some embodiments, the occlusion device can belocated in the patient interface.

Another preferred embodiment involves a method of providing continuouspositive airway pressure and resuscitation to an infant, including usingan inspiratory pressure device to provide a flow of breathing gas, theinspiratory pressure device capable of generating a peak inspiratorypressure in the flow of breathing gas. The flow of breathing gas issupplied to an infant patient through a patient interface and expiratorygases are received from the infant patient through the patientinterface. A water resistance valve or other type of oscillatoryresistance valve is utilized to vent the flow of breathing gas andexpiratory gases and maintain a mean positive end expiration pressurewithin the patient interface that is less than the peak inspiratorypressure. A resuscitation breath is provided to the infant patient byblocking the flow of breathing gas and expiratory gases between thepatient interface and the water resistance valve such that the pressurewithin the patient interface increases to the peak inspiratory pressure.

In some applications, the method can include providing repeatedresuscitation breaths to the infant patient by repeatedly alternatingbetween blocking and allowing the flow of breathing gas and expiratorygases between the patient interface and the water resistance valve. Insome applications, the blocking of the flow of breathing gas andexpiratory gases between the patient interface and the water resistancevalve can be accomplished by actuating a push button occlusion valve orby clamping a portion of an expiratory tube. In some applications, theflow of breathing gas can be passed through a humidifier after theinspiratory pressure device and before the patient interface. Thepositive end expiration pressure can be adjusted by adjusting a depth ofan outlet of the flow of breathing gas and expiratory gases within awater reservoir of the water resistance valve.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments, having certain features, aspects and advantagesof the present invention, are described with reference to theaccompanying drawings. The drawings contain six (6) figures.

FIG. 1 is an illustration of an infant patient receiving CPAP therapyand/or resuscitation therapy from a system including an inspiratorypressure device, a humidifier, a patient interface and an expiratorypressure device.

FIG. 1A is an illustration of an infant patient and an alternativepatient interface.

FIG. 2 is a partial cross-sectional view of a linear motion, push buttonocclusion valve.

FIGS. 3A and 3B are partial cross-sectional views of a clamp-typeocclusion valve in which a tube can be collapsed or occluded by a clamp.FIG. 3A shows the tube in an open configuration and FIG. 3B shows thetube in a collapsed or occluded configuration.

FIG. 4 is an illustration of a modification of the system of FIG. 1, inwhich the inspiratory pressure device is integrated with the humidifier.

FIG. 5 is a partial sectional view of the integrated inspiratorypressure device and humidifier of FIG. 4.

FIG. 6 is an illustration of another modification of the system of FIG.1, in which a flow generator is integrated with the humidifier.

DETAILED DESCRIPTION

FIG. 1 illustrates a combination infant positive airway pressure (PAP)or continuous positive airway pressure (CPAP) and resuscitation system,generally referred to by the reference numeral 10. The system 10 iscapable of providing PAP or CPAP therapy to a neonate or an infantpatient 12 for an extended period of time, while also permittingresuscitation breaths to be delivered to the infant patient 12 if orwhen necessary. Preferably, both the PAP or CPAP therapy and theresuscitation breaths are delivered through a single patient interface14 without requiring removal of the interface 14 from the infant patient12. The present system 10 is disclosed herein in the context ofcontinuous positive airway pressure (CPAP) therapy; however, the system10 could also provide other types or modes of positive airway pressure(PAP) therapy. Accordingly, references to CPAP therapy herein areunderstood to also include other types of PAP therapies, unlessspecifically noted otherwise.

The illustrated system 10 includes a source of breathing gas 20, whichcan be a gas cylinder (not shown), a wall supply 20, or any othersuitable source of breathing gas. The breathing gas can be air, oxygen,a blend of air and oxygen, or any other suitable gas for use inrespiratory therapy. The source of breathing gas 20 provides a flow ofbreathing gas at an initial feed pressure or within an initial feedpressure range. The flow rate of the flow of breathing gas can beadjusted by a suitable flow meter or gas blender 22 to a suitable levelfor the desired therapy.

A suitable conduit, such as a gas supply line 24 supplies the flow ofbreathing gas to an inspiratory pressure device 26, which can be aresuscitator. More preferably, the inspiratory pressure device 26 is aninfant resuscitator, such as an infant resuscitator sold by Fisher andPaykel Healthcare, the Assignee of the present application, under theNEOPUFF trademark. Although referred to herein as a “resuscitator” forconvenience, it is understood that the term can encompass other suitabletypes of inspiratory pressure devices capable of providing a breathinggas at a controlled output pressure.

Preferably, the resuscitator 26 is capable of receiving a flow ofbreathing gas from the source of breathing gas 20 and outputting theflow of breathing gas at a controlled pressure greater than atmosphericpressure. In particular, the resuscitator 26 can output the flow ofbreathing gas at a peak inspiratory pressure (PIP), which preferably canbe up to about 75 cmH₂O or greater. Preferably, the resuscitator 26includes an adjustment mechanism, such as an adjustment valve 28, whichallows the PIP to be adjusted to a desired pressure level. Preferably,the resuscitator 26 also incorporates a pressure relief valve 30 thatregulates a maximum pressure within the system 10. The pressure reliefvalve 30 can be adjustable such that the maximum system pressure can beadjusted. For example, an adjustment range can be between about 5-70cmH₂O. The pressure relief level can be factory set to a particularvalue, such as about 40 cmH₂O, for example. However, in alternativearrangements, a separate pressure regulator could be provided within thesystem 10 to regulate the maximum system pressure. Such a pressureregulator is described in U.S. Pat. No. 6,644,313, which is incorporatedby reference herein in its entirety. In embodiments having a blowerunit, a pressure relief valve may not be necessary because the maximumachievable pressure of the system can be regulated by the blower unit.The blower unit can be designed so that the maximum pressure it canproduce is lower than a desired pressure relief level. In otherembodiments, the maximum achievable pressure of the blower unit can belimited by software in the system.

The flow of breathing gas outputted from the resuscitator 26 preferablyis delivered to an optional humidifier system 32 by a suitable conduit,such as an inspiratory tube or supply tube 34. In some embodiments, theresuscitator and the humidifier system can be integrated into a singleunit, as discussed below. The humidifier system 32 provides humidity orvaporized liquid, such as water, to the flow of breathing gas receivedfrom the resuscitator 26 to output a flow of humidified breathing gas tothe patient interface 14 through a suitable conduit, such as a supplytube 36. The humidifier system 32 can include a humidifier unit orhumidifier 40 and a humidity chamber 42. The humidity chamber 42 holds avolume of liquid, such as water, which is heated by the humidifier 40 tocreate a vapor within the humidity chamber 42 that is transferred to theflow of breathing gas. The humidity chamber 42 can be an auto-fillvariety, in which a source of liquid 44 is connected to the humiditychamber 42 to refill the volume of liquid, as appropriate. A suitablehumidifier 40 is the MR850 Humidifier sold by the Assignee of thepresent application. A suitable humidity chamber 42 is the MR225 orMR290 humidity chamber sold by the Assignee of the present application.The humidifier system 32 can output a flow of humidified breathing gasat a desired temperature and absolute humidity, such as an optimaltemperature of about 37 degrees Celsius and absolute humidity of about44 mg/L, or within a desirable or acceptable range of the optimaltemperature and absolute humidity.

The supply tube 36 can be a heated supply tube such that a temperatureof the flow of breathing gas is maintained at an elevated level withinthe supply tube 36 and to avoid or limit condensation within the supplytube 36 or patient interface 14. A heating element cable 46 can connecta heating element of the supply tube 36 to the humidifier 40 (or otherpower/heat source) to power the heating element. A sensor or probe 48can be coupled to the humidifier 40 and supply tube 36 to detect thetemperature and/or flow rate of the flow of breathing gas through thesupply tube 36. Preferably, the sensor 48 is spaced from the inlet endof the supply tube 36 and can be located at the outlet end of the supplytube 36. The sensor 48 can include a wire that couples the sensor 48 tothe humidifier 40. The humidifier 40 can utilize information from thesensor 48 to control the operating parameters of the humidifier 40, forexample, to maintain the temperature and/or humidity of the flow ofbreathing gas within the supply tube 36 at a desirable level or range.

From the humidifier system 32, the flow of breathing gas is supplied tothe patient interface 14, which can be any suitable type of interfacecapable of supplying a breathing gas to the respiratory system of thepatient. The illustrated interface 14 is a lateral nasal interface,which includes nasal cannula or nasal prongs that are inserted into thenostrils of the infant patient 12. In a lateral interface, the inlet andoutlet are laterally spaced on opposing sides of the nasal cannula orprongs and a midline of the infant patient 12. FIG. 1A illustrates analternative nasal interface 14A, which can be referred to as a midlinenasal interface. The midline nasal interface 14A positions the inlet andthe outlet of the interface 14A are located in line with the nasalcannula or nasal prongs and substantially along the midline of theinfant patient 12. The inlet and outlet of the interface 14A can bepositioned side-by-side; however, in a preferred arrangement, the inletand outlet are stacked one on top of the other. One suitable interface14A is an infant nasal tube or mask in combination with nasal prongssold by the Assignee of the present application under the trademarkFLEXITRUNK. However, other suitable patient interfaces 14 can also beused, such as a face mask that covers both the nose and mouth of theinfant patient 12 (e.g., RD Series Infant Resuscitation Masks sold bythe Assignee of the present application) or an appropriate interfacedevice in combination with an endotracheal tube. An infant resuscitationmask is described in U.S. Pat. No. 7,341,059, which is herebyincorporated by reference in its entirety.

Preferred interfaces 14 provide a sealed system that delivers the flowof breathing gas to the infant patient 12 and receives expiratory gasesfrom the patient 12. Preferably, the system 10 is a biased flow systemin which breathing gas is constantly flowing within the system 10generally in a direction from the inlet of the patient interface 14 tothe outlet of the patient interface 14. Thus, the infant patient 12 caninhale a portion of the flow of breathing gas and the remainder ispassed through the patient interface 14. Exhaled or expiratory gases canmix with the flow of breathing gas and exit the patent interface 14along with the unused portion of the flow of breathing gas. Forconvenience, the gases exiting the patient interface 14 are referred toas expiratory gases or the flow of breathing gas, although it isunderstood that either or both of patient exhaled gases and unusedbreathing gases can be present at any particular point in time.

Expiratory gases flow from the patient interface 14 to an expiratorypressure device 60, which is configured to regulate the minimum pressurewithin the system 10, preferably to a level above ambient or atmosphericpressure. Preferably, the expiratory pressure device 60 is connected tothe patient interface 14 by a suitable conduit, such as an expiratoryhose 62. However, in an alternative arrangement, the expiratory pressuredevice 60 can be connected directly to or integrated with the patientinterface 14.

Preferably, the expiratory pressure device 60 is configured to provide aminimum pressure or minimum backpressure within the system 10 and, inparticular, at the patient interface 14, which can be referred to as thepositive end expiration pressure (PEEP). In the illustrated system 10,the PEEP is equivalent to, or generally equivalent to, the continuouspositive airway pressure (CPAP). Accordingly, such a device can bereferred to as a CPAP generator. However, preferably, the expiratorypressure device 60 is an oscillatory valve capable of providing pressureoscillations relative to a mean PEEP pressure. It is believed that suchpressure oscillations are beneficial to the infant patent 12 and mayresult in improved gas exchange and reduce the infant patient's 12 workof breathing. Thus, an oscillatory pressure expiratory pressure device60 is particularly preferred. One type of oscillating pressureexpiratory pressure device 60 is a fluid resistance valve, in particulara liquid or water resistance valve, which is often referred to as abubbler. In general, a water resistance valve delivers the expiratorygases to an outlet that is submerged in a water reservoir resulting in aresistance to the exit of the expiratory gases that is greater than thatcaused by ambient or atmospheric pressure and related to the depth ofthe outlet relative to a surface of the water within the waterreservoir. In some arrangements, the depth of the outlet is adjustableto allow the PEEP to be adjusted to a desired level. One suitablebubbler is the Bubble CPAP generator sold by the Assignee of the presentapplication. Additional details of a suitable bubbler device aredescribed in U.S. Pat. No. 6,805,120, which is incorporated by referenceherein in its entirety. Preferably, the bubbler (or other oscillatorypressure device) is capable of producing vibrations in the infantpatient's chest at a frequency of between about 5-30 Hz.

The illustrated system 10 also includes an occlusion device or occlusionvalve 70 that is configured to selectively block the flow of gaseswithin the system 10 and preferably block the flow of expiratory gases,such as within the patient interface 14, expiratory tube 62 orexpiratory pressure device 60. Preferably, the occlusion valve 70 islocated upstream of the expiratory pressure device 60 and downstream ofthe patient interface 14, such as within the expiratory tube 62.Preferably, the occlusion valve 70 is located at or near the patientinterface 14, such as within about 500 millimeters or less of thepatient interface 14. However, in other arrangements, the occlusionvalve 70 can be integrated with the patient interface 14 or expiratorypressure device 60. The occlusion valve 70 is configured to block theexit of gases from the system 10 to a sufficient extent such that thegas pressure within the system 10 rises above the PEEP. With the exit ofgases from the system 10 blocked, the inspiratory pressure device 26 canincrease the pressure in the system 10 preferably to or near the set PIPlevel. The occlusion valve 70 can completely or substantially completelyblock the flow of gas within the system 10, or can block or interruptthe flow to a sufficient extent to allow the inspiratory pressure device26 or integrated unit 90 to raise the pressure toward the PIP.Preferably, the occlusion valve 70 can block the flow of gas within thesystem 10 to a sufficient extent that the inspiratory pressure device 26or integrated unit 90 can raise the pressure within the system 10 to orsubstantially to the PIP pressure. However, to quickly and accuratelyachieve the PIP pressure, it is desirable that the occlusion valve 70completely or substantially completely block the flow of gas within thesystem 10. Although described as a sealed system, it is understood thatsome leakage of gas may occur from the system 10, such as between thepatient interface 14 and the patient 12, for example. In addition,pressure losses may occur throughout the system 10 such that thepressure is not the same throughout the entire system 10. Accordingly,it is understood that the PEEP or PIP may vary between the point ofmeasurement and some other point within the system 10. Therefore, it isunderstood that discussion of specific pressures or pressure rangesherein, such as PIP or PEEP, incorporates a range of acceptablevariation, which can result from pressure leakage, pressure loss ormeasurement error.

In operation, the occlusion valve 70 can be utilized to perform aresuscitation procedure or resuscitation therapy by raising the pressurewithin the system 10 to at or near the PIP pressure to deliver aresuscitation breath to the infant patient 12 in a manner similar to aconventional resuscitation procedure. However, advantageously, with thepresent system 10, resuscitation breaths can be provided to an infantpatient 12 that is undergoing CPAP therapy immediately and withoutrequiring additional equipment or set-up. Furthermore, the CPAP therapycan be immediately resumed after the resuscitation procedure.Preferably, the resuscitation breaths can be provided through the samepatient interface 14 as the CPAP therapy without removal or exchange ofthe interface and with breathing gases flowing in the same directionwithin the system 10 as the CPAP therapy. The occlusion valve 70 can beused to provide repeated resuscitation breaths to the infant patient 12at or near PIP pressure with intervening periods of PEEP. Theresuscitation breaths delivered by use of the occlusion valve 70 can beat any suitable rate, such as about 40-60 breaths per minute. Therelative duration of the resuscitation breath time at PIP pressure tothe exhalation time at PEEP can be any suitable ratio, such as 40:60,50:50, 60:40, or any value in between. The resuscitation proceduretypically lasts for less than 30 minutes or less than 15 minutes. Often,the resuscitation procedure lasts between about 3-5 minutes. Thus, thepresent system 10 is particularly advantageous in reducing theswitchover time between CPAP therapy and resuscitation therapy, whichavoids delay in providing resuscitation therapy once it is recognized asnecessary or desirable.

The occlusion valve 70 can be of any suitable arrangement or structureto selectively accomplish a partial or complete occlusion of gas flowwithin the system 10. Preferably, the occlusion valve 70 allows thecycling between an occluded or closed position and an open position at asuitable rate, such as the rates described herein. In some arrangements,the occlusion valve 70 is a manual valve that is operated by manually bya caregiver. Accordingly, preferably the occlusion valve 70 facilitatesrepeated cycling between the open and closed position multiple times perminute.

For example, FIG. 2 illustrates a push button valve arrangement 70having a manually operated push button 72 that actuates a valve body 74movable between an open position and a closed position. The valve body74 can simply move into or out of a flow passage P of the system 10(linear movement or translation) to selectively allow and occlude gasflow within the system 10. In some embodiments, the valve arrangementcan include a safety feature to help prevent accidental actuation. Forexample, the push button may be lockable in the open position byrotating the push button a quarter turn. In order to use the valvearrangement, the user can rotate the push button to unlock beforeactuating. Preferably, the valve body 74 is biased to the open positionby a biasing member, such as a spring 76, so that gas flow is normallyunobstructed. The valve body 74 can be movable to the closed position(e.g., using the manual push button 72) when it is desired to deliver aresuscitation breath at PIP. In other arrangements, the valve 70 couldbe a rotatable valve, such as a stopcock. FIG. 3 illustrates anotherpossible occlusion valve arrangement 70, in which a compliant section oftubing 78 that has sufficient resilience to remain open in the absenceof an external force (FIG. 3A), but can be collapsed to a closedposition in response to an external squeezing force (FIG. 3B), such as aforce applied by a clamping mechanism 79. In still other arrangements,the valve 70 could be automatically movable (e.g., electronicallyactuated).

As described, the occlusion valve 70 can be positioned in any suitablelocation within the system 10. The system 10 can be considered to havean inspiratory circuit and an expiratory circuit. In the illustratedarrangement, the inspiratory circuit can include all or portions of thesource of breathing gas 20, the gas supply line 24, the inspiratorypressure device 26, the supply tube 34, the humidifier system 32, andthe supply tube 36. The expiratory circuit can include all or portionsof the expiratory tube 62 and the expiratory pressure device 60. Aportion of the patient interface 14 can be predominantly occupied by aflow of inspiratory breathing gas prior to inspiration by the infantpatient 12 or prior to availability to the infant patient 12, whileanother portion of the patient interface 14 can be predominantlyoccupied by a flow of expiratory gas exhaled by the infant patient 12 orthat has bypassed the infant patient 12. Accordingly, the patientinterface 14 can be considered to form a part of each of the inspiratorycircuit and the expiratory circuit. A portion of the patient interface14 can also include a mixture of inspiratory gas and expiratory gas, atleast for certain time durations, and may not be considered part ofeither of the inspiratory circuit or the expiratory circuit or may beconsidered as a part of each.

The various components of the system 10, including those describedabove, can be arranged and/or mounted in any suitable manner. Some orall of the components can be stationary (e.g., wall mounted) or movable.In the illustrated arrangement, some of the components are mounted to asupport pole 80, which includes a base portion 82 having a plurality ofrollers or casters 84 to provide mobility. A suitable pole 80 is the900MR292 or 900MR293 pole sold by the Assignee of the presentapplication. In the illustrated arrangement, the inspiratory pressuredevice 26, the humidifier system 32 and the expiratory pressure device60 are mounted to the support pole 80. Although not specificallyillustrated, the source of water 44 preferably is also supported by thesupport pole 80. In other arrangements, some of the components could bemounted on another support pole 80. The source of breathing gas 20 andthe flow meter or gas blender 22 can be mobile or can be stationary(e.g., wall mounted). In one arrangement, for example, the resuscitator26 can be integrated with an infant warmer, such as the 900 Seriesinfant warmers sold by the Assignee of the present invention.

To set up the system 10 for use, the components can be gathered andmounted to the support pole 80 or other support structure, if necessaryor desired. The components can be connected to a power source, ifnecessary, and turned on. The inspiratory pressure device 26 can becoupled to the source of breathing gas 20 through the flow meter or gasblender 22 by the gas supply line 24. The humidifier system 32 can becoupled to the inspiratory pressure device 26 by the supply tube 34. Thesource of water 44 can be coupled to the humidity chamber 42. Thepatient interface 14 can be coupled to the humidifier system 32 by thesupply tube 36. The expiratory pressure device 60 can be coupled to thepatient interface 14 by the expiratory tube 62. The occlusion valve 70can be integrated into the expiratory tube 62; however, the occlusionvalve 70 can also be assembled to the expiratory tube 62 (such asintermediate two tube portions of the expiratory tube 62) or otherwiseassembled in a suitable location within the system 10, as describedabove.

If necessary, the expiratory pressure device 60 can be filled with aliquid, such as about 500 milliliters of water. If adjustable, theexpiratory pressure device 60 can be initially adjusted to a maximumpressure level (maximum PEEP). The humidifier system 32 can be adjustedto a desired temperature and absolute humidity, such as about 37 degreesCelsius and 44 mg/L. The flow meter or gas blender 22 can be adjusted toa desired flow rate, preferably less than 15 liters per minute (LPM). Inembodiments having a blower unit, the flow meter or gas blender can beintegrated with the blower unit. More preferably, the flow rate isadjusted to between about 6-8 LPM.

If necessary or desirable, the pressure relief valve 30 of theinspiratory pressure device 26 can be adjusted to a suitable pressurerelief level. The pressure relief valve 30 can be factory set to apressure relief level, such as about 40 cmH₂O. The pressure relief valve30 can be set to a lower level, such as between about 5-70 cmH₂O and,more preferably, 30-40 cmH₂O. To set the level of the pressure reliefvalve 30, the PIP adjustment of the inspiratory pressure device 26 isadjusted to a maximum level. The patient interface 14 can be blocked orconnected to a test lung apparatus, such as the RD020-01 test lungapparatus sold by the Assignee of the present application. The occlusionvalve 70 can be actuated to allow the pressure within the system 10 torise to the pressure relief level, which can be adjusted to a desiredlevel. With the occlusion valve 70 still actuated, the PIP can beadjusted to a desirable level, preferably less than about 75 cmH₂O. Morepreferably, the PIP is between about 10-40 cmH₂O or 20-30 cmH₂O. In oneapplication, the PIP pressure is adjusted to about 20 cmH₂O, using thePIP valve 28. The occlusion valve 70 can be moved to an open positionsuch that the system pressure is reduced to the PEEP value as determinedby the expiratory pressure device 60. The PEEP level can be adjusted toa desirable pressure, such as less than about 25 cmH₂O, by adjusting adepth of the gas outlet within the water reservoir. Preferably, the PEEPlevel is adjusted to less than about 15 cmH₂O, less than about 9 cmH₂Oor less than about 5 cmH₂O. In one application, the PEEP level is set toabout 5 cmH₂O. If necessary, the test lung apparatus can be removed andthe system 10 is ready for use.

To use the system 10, the patient interface 14 can be applied to aninfant patient 12 following an appropriate methodology. For example, aface mask can be positioned over the nose and mouth of the infantpatient 12 and, if desired, held in place by hand, a strap or otherretention device. If an endotracheal tube is used, the interface 14 orportion of the interface 14 can be coupled to the endotracheal tube. Inthe illustrated arrangement, the nasal prongs can be coupled to thenasal mask or tube and the nasal prongs can be inserted into thenostrils of the infant patient 12. The nasal mask 14 can be held inplace by any suitable retention mechanism, such as a chin strap or headstrap.

Once the patient interface 14 is in place on the infant patient 12, theCPAP therapy can be commenced. A flow of breathing gas is supplied tothe infant patient 12 by the patient interface 14 at the CPAP or PEEPlevel, as regulated by the expiratory pressure device 60. As discussed,preferably the expiratory pressure device 60 is configured to producepressure oscillations within the system 10, which is believed to have animproved therapeutic effect on the infant patient 12. The CPAP therapycan continue for a desired period of time.

If necessary or desirable, resuscitation therapy can be administered. Asdescribed above, the occlusion valve 70 can be actuated to block theexit of expiratory gases from the system 10 and cause the pressurewithin the system 10 to rise toward or to the PIP pressure to deliver aresuscitation breath to the infant patient 12. The occlusion valve 70can be moved to an open position, or allowed to return to an openposition, to return the system to the PEEP. In some arrangements, theactuation of the occlusion valve 70 is accomplished manually. Theactuation and release of the occlusion valve 70 can be repeated at adesired frequency, such as between about 40-60 breaths per minute, for asuitable duration, such as about 3-5 minutes. However, if necessary ordesirable, the duration of the resuscitation therapy can be up to 15-30minutes, or longer. At the conclusion of the resuscitation therapy, thesystem 10 can automatically return to the CPAP mode at the PEEP.Accordingly, with the illustrated system 10, resuscitation therapy canbe immediately commenced on an infant patient 12 that is undergoing CPAPtherapy without requiring the set-up of additional equipment and withoutrequiring the replacement of the patient interface 14.

FIGS. 4 and 5 illustrate a modification of the system 10 of FIG. 1.Because the system of FIGS. 4 and 5 is similar to the system 10 of FIG.1 in many respects, the same reference numbers are used to indicationthe same or corresponding components. In the system of FIGS. 4 and 5,the resuscitator 26 (or other inspiratory pressure device) is integratedwith the humidifier 32 in a resuscitator/humidifier unit 90 (hereinafter“integrated unit 90”). In addition, preferably, the source of breathinggas 20 is or includes ambient air from an environment adjacent theintegrated unit 90. Therefore, the integrated unit 90 preferablycomprises a flow generator or flow source, such as a fan, gas pump orblower 92 (FIG. 5), which generates a flow of air. In some embodiments,however, the integrated unit 90 can be connected to a source ofbreathing gas, such as a gas cylinder or a wall supply, instead of or inaddition to the flow generator. In some arrangements, the system canutilize supplemental breathing gases (oxygen or other suitablerespiratory gases) that are blended in combination with air. However, inmany arrangements, only air is used and the source of breathing gas(reference number 20 in FIG. 1) can be omitted.

In the illustrated arrangement, the integrated unit 90 generates a flowof breathing gas (e.g., air) and outputs the flow of breathing gas at acontrolled pressure greater than atmospheric pressure to the humidifier,which humidifies the flow of breathing gas. The flow of humidifiedbreathing gas is delivered to the patient 12 via the supply tube 36 andpatient interface 14. Exhaled and unused gases are delivered to theexpiratory pressure device 60 via the expiratory hose 62. The expiratorypressure device 60 can provide a minimum pressure or minimumbackpressure within the system and, in particular, at the patientinterface 14 preferably to or near the PEEP pressure. The occlusionvalve 70 can be used to block the flow of breathing gas such that theinspiratory pressure device 26 can increase the pressure in the systempreferably to or near the set PIP level. The system of FIGS. 4 and 5preferably operates in substantially the same manner as described abovewith respect to the system 10 of FIG. 1.

With reference to FIG. 5, in addition to the blower 92, the integratedunit 90 preferably includes a filter 94 upstream from the blower 92. Thefilter 94 is of a suitable arrangement to separate impurities or otherundesirable elements from the ambient air that is used to generate theflow of air within the system. The filter 94 and the blower 92preferably can be coupled to or contained within a housing 96 thatcontains portions of the humidifier 40 and supports the humidifierchamber 42. The pressure adjustment valve 28 and a manometer 98, orother pressure gauge or measurement device, can be coupled to orcontained within a housing 100 that is separate from the housing 96.Preferably, the housing 100 can be removable from the housing 96. Whenthe housing 100 is removed, the integrated unit 90 can be used as ablower 92 and humidification system 32 without the resuscitationfeature. In the illustrated arrangement, the housing 100 defines orcontains a conduit 102 for delivering the flow of breathing gas from theblower 92 to the humidification chamber 42 of the humidifier system 32.When the housing is removed, an auxiliary conduit (not shown) can beutilized in place of the conduit 102. Alternatively, an auxiliaryconduit can be integrated with or otherwise incorporated with thehousing 96 that is utilized when the housing 100 is removed. A valvearrangement could be configured to automatically switch between theconduit 102 and the auxiliary conduit depending on the presence orabsence of the housing 100.

With reference to FIG. 6, in another modification of the systems of FIG.1 and FIGS. 4 and 5, the flow generator (hereinafter “blower 92”) isintegrated with the humidifier 40 of the humidification system 32.However, unlike the system of FIGS. 4 and 5, the resuscitator 26 is aseparate system component from the humidifier 40, humidification chamber42 or the entire humidifier system 32. Thus, in the system of FIG. 6,the blower 92 is connected to the resuscitator 26 via the supply line 24to deliver the flow of air (or other breathing gas) from the blower 92to the resuscitator 26. The flow of air then flows from the resuscitator26 to the humidification chamber 42 of the humidifier system 32 and tothe patient 12 as described above. If the resuscitator 26 is notnecessary or desired, the blower 92 can be connected to thehumidification chamber 42 of the humidifier system 32, without passingthrough the resuscitator 26, via a suitable internal or externalauxiliary conduit, as described above.

Although described in the context of an infant patient system, theillustrated system can be used in, or modified for use in, otherapplications or contexts, as well. Thus, although this invention hasbeen disclosed in the context of certain preferred embodiments andexamples, it will be understood by those skilled in the art that thepresent invention extends beyond the specifically disclosed embodimentsto other alternative embodiments and/or uses of the invention andobvious modifications and equivalents thereof. In particular, theskilled artisan will appreciate, in view of the present disclosure, thatcertain advantages, features and aspects of the system may be realizedin a variety of other applications, many of which have been noted above.Additionally, it is contemplated that various aspects and features ofthe invention described can be practiced separately, combined together,or substituted for one another, and that a variety of combination andsubcombinations of the features and aspects can be made and still fallwithin the scope of the invention. Thus, it is intended that the scopeof the present invention herein disclosed should not be limited by theparticular disclosed embodiments described above, but should bedetermined only by a fair reading of the claims.

What is claimed is:
 1. A combination infant positive airway pressure andresuscitation system, comprising: an inspiratory pressure device thatoutputs a flow of breathing gas at a desired peak inspiration pressure;an inspiratory circuit that receives the flow of breathing gas from theinspiratory pressure device; a patient interface that receives the flowof breathing gas from the inspiratory circuit, wherein the patientinterface is configured to deliver the flow of breathing gas to apatient and receive expiratory gases from the patient; an expiratorycircuit that receives the expiratory gases from the patient interface;an expiratory pressure device that receives expiratory gases from theexpiratory circuit and regulates the expiratory gases to a positive endexpiration pressure; an occlusion device located at the patientinterface and upstream of the expiratory pressure device, wherein theocclusion device is configured to selectively occlude the expiratorycircuit at desired times such that the pressure within the inspiratorycircuit rises to the peak inspiration pressure.
 2. The combinationinfant positive airway pressure and resuscitation system of claim 1,wherein the expiratory pressure device comprises a water resistancevalve.
 3. The combination infant positive airway pressure andresuscitation system of claim 1, wherein the occlusion device comprisesa manual push button valve.
 4. The combination infant positive airwaypressure and resuscitation system of claim 1, wherein the occlusiondevice comprises a clamp.
 5. The combination infant positive airwaypressure and resuscitation system of claim 1, wherein the occlusiondevice is a lockable occlusion device.
 6. The combination infantpositive airway pressure and resuscitation system of claim 1, whereinthe occlusion device is biased towards an open position.
 7. Thecombination infant positive airway pressure and resuscitation system ofclaim 1, wherein the occlusion device is electronically actuated.
 8. Acombination infant positive airway pressure and resuscitation system,comprising: an inspiratory pressure device comprising a resuscitator,wherein the resuscitator is configured to regulate a flow of breathinggas to a desired peak inspiration pressure; an expiratory pressuredevice configured to receive expiratory gases from an expiratory circuitand regulate the expiratory gases to a positive end expiration pressure;an occlusion device located at a patient interface and located upstreamof the expiratory pressure device, wherein the occlusion device isconfigured to selectively occlude the expiratory circuit at desiredtimes such that the pressure within the inspiratory circuit rises to thepeak inspiration pressure of the resuscitator.
 9. The combination infantpositive airway pressure and resuscitation system of claim 8, whereinthe expiratory pressure device comprises a water resistance valve. 10.The combination infant positive airway pressure and resuscitation systemof claim 8, wherein the occlusion device comprises a manual push buttonvalve.
 11. The combination infant positive airway pressure andresuscitation system of claim 8, wherein the occlusion device comprisesa clamp.
 12. The combination infant positive airway pressure andresuscitation system of claim 8, wherein the occlusion device is alockable occlusion device.
 13. The combination infant positive airwaypressure and resuscitation system of claim 8, wherein the occlusiondevice is biased towards an open position.
 14. The combination infantpositive airway pressure and resuscitation system of claim 8, whereinthe occlusion device is electronically actuated.
 15. A patient interfacefor a combination infant positive airway pressure and resuscitationsystem, comprising: an inlet configured to connect to a source ofrespiratory gases and receive respiratory gases from the source; anoutlet configured to connect to an expiratory circuit and to deliverexpiratory gases to the expiratory circuit; an occlusion deviceintegrated with the patient interface and configured to selectivelyocclude the expiratory circuit at desired times such that the pressurewithin the system rises above a positive end expiration pressure. 16.The patient interface for a combination infant positive airway pressureand resuscitation system of claim 15, wherein the occlusion devicecomprises a manual push button valve.
 17. The patient interface for acombination infant positive airway pressure and resuscitation system ofclaim 15, wherein the occlusion device is a lockable occlusion device.18. The patient interface for a combination infant positive airwaypressure and resuscitation system of claim 15, wherein the occlusiondevice is biased towards an open position.
 19. The patient interface fora combination infant positive airway pressure and resuscitation systemof claim 15, wherein the occlusion device is electronically actuated.